Plants are killed in the winter by frost

Options

A. Because of desiccation and mechanical damages to the tissues
B. Because no photosynthesis takes place at such low temperature
C. Because respiration ceases at such low temperature
D. Because there is no transpiration

Answer

**Step-by-Step Solution:**

1. **Understanding Frost Damage**: Frost occurs when temperatures drop below freezing, causing water within plant cells to freeze. This freezing can lead to cell damage and death.

2. **Desiccation and Mechanical Damage**: When water in plant cells freezes, it expands, which can rupture cell membranes. This mechanical damage is a significant factor in plant death during frost.

3. **Metabolic Processes**: Low temperatures affect the metabolic processes in plants. While respiration does not completely cease, it slows down significantly, reducing the plant's ability to function and recover.

4. **Transpiration**: Transpiration, the process of water movement through a plant and its evaporation from aerial parts, is also affected. At low temperatures, transpiration rates decrease, leading to a lack of water availability for the plant.

5. **Conclusion**: The primary reason plants are killed by frost is due to desiccation and mechanical damage to tissues caused by the freezing of water in their cells. Other processes like photosynthesis and respiration do not completely stop but are severely hindered.

**Final Answer**: The correct reason why plants are killed in winter by frost is due to desiccation and mechanical damage to the tissue.

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